return headers.get(key);
}
// 此处的 getter 手动写, 自动生成的版本是直接得到整个 hash 表.
// 而我们需要的是根据 key 来获取值.
public String getCookie(String key) {
return cookies.get(key);
}
public String getPararmeters(String key) {
return parameters.get(key);
}
@Override
public String toString() {
return “HttpRequest{” +
“method '” + method + ‘’’ +
“, url '” + url + ‘’’ +
“, version '” + version + ‘’’ +
", headers " + headers +
", parameters " + parameters +
", cookies " + cookies +
“, body '” + body + ‘’’ +
‘}’;
}
}
实现返回响应
=====================================================================
• 注释详解
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.util.HashMap;
import java.util.Map;
public class HttpRespond {
private String version = “HTTP/1.1”;
private int statue; // 状态码
private String message; // 状态码的描述信息
private Map<String, String> headers = new HashMap<>();
private StringBuilder body = new StringBuilder(); // 方便一会进行拼接.
// 当代码需要把响应写回给客户端的时候, 就往这个 OutputStream 中写就好了
private OutputStream outputStream;
// 表示一个 HTTP 响应, 负责构造
// 进行序列化操作
public static HttpRespond build(OutputStream outputStream) {
HttpRespond respond = new HttpRespond();
respond.outputStream = outputStream;
// 除了 outputStream 之外, 其他的属性的内容, 暂时都无法确定. 要根据代码的具体业务逻辑
// 来确定. (服务器的 “根据请求并计算响应” 阶段来进行设置的)
return respond;
}
public void setVersion(String version) {
this.version = version;
}
public void setStatue(int statue) {
this.statue = statue;
}
public void setMessage(String message) {
this.message = message;
}
public void setHeaders(String key, String value) {
this.headers.put(key, value);
}
public void setBody(String body) {
this.body.append(body);
}
// 以上的设置属性的操作都是在内存中倒腾.
// 还需要一个专门的方法, 把这些属性 按照 HTTP 协议 都写到 socket 中.
public void flush() throws IOException {
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream));
String firstLine = version + " " + statue + " " + message;
bufferedWriter.write(firstLine + “\n”);
headers.put(“Content-Length”, body.toString().getBytes().length + “”);
for (Map.Entry<String, String> entry : headers.entrySet()) {
bufferedWriter.write(entry.getKey() + ": " + entry.getValue() + “\n”);
}
bufferedWriter.write(“\n”);
bufferedWriter.write(body.toString() + “\n”);
bufferedWriter.flush();
}
}
实现Http Sever
===========================================================================
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class HttpSeverV3 {
//设置一个静态内部类表示user
static class User {
public String username;
public String password;
public User(String username, String password) {
this.username = username;
this.password = password;
}
@Override
public String toString() {
return “User{” +
“username='” + username + ‘’’ +
“, password='” + password + ‘’’ +
‘}’;
}
}
private ServerSocket serverSocket;
// session 会话. 指的就是同一个用户的一组访问服务器的操作, 归类到一起, 就是一个会话.
// 记者来采访你, 记者问的问题就是一个请求, 你回答的内容, 就是一个响应. 一次采访过程中
// 涉及到很多问题和回答(请求和响应), 这一组问题和回答, 就可以称为是一个 “会话” (整个采访的过程)
// sessions 中就包含很多会话. (每个键值对就是一个会话)
private Map<String, User> sessions = new HashMap<>();
public HttpSeverV3(int port) throws IOException {
this.serverSocket = new ServerSocket(port);
}
public void start() throws IOException {
System.out.println(“服务器启动”);
ExecutorService executorService = Executors.newCachedThreadPool();
while (true) {
Socket clientSocket = serverSocket.accept();
executorService.execute(new Runnable() {
@Override
public void run() {
process(clientSocket);
}
});
}
}
private void process(Socket clientSocket) {
try {
HttpRequest request = HttpRequest.build(clientSocket.getInputStream());
HttpRespond respond = HttpRespond.build(clientSocket.getOutputStream());
if (request.getMethod() != null) {
//判断请求是什么方法 不同方法不同处理
if (“GET”.equalsIgnoreCase(request.getMethod())) {
doGet(request, respond);
} else if (“POST”.equalsIgnoreCase(request.getMethod())) {
doPost(request, respond);
} else {
respond.setHeaders(“Content-type”, “text/html”);
respond.setStatue(404);
respond.setMessage(“No Found”);
respond.setBody(“
NULL
”); 
}
//写入
respond.flush();
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
clientSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
private void doPost(HttpRequest request, HttpRespond respond) throws IOException {
if (request.getUrl().startsWith(“/login”)) {
System.out.println(request);
//判断登录名和密码是否正确
String userName = request.getPararmeters(“username”);
String password = request.getPararmeters(“password”);
if (“123”.equals(userName) && “aaa”.equals(password)) {
//登录成功
respond.setStatue(200);
respond.setMessage(“OK”);
respond.setHeaders(“Content-type”, “text/html”);
//通过cookie让浏览器记住你
// 现有的对于登陆成功的处理. 给这次登陆的用户分配了一个 session
// (在 hash 中新增了一个键值对), key 是随机生成的. value 就是用户的身份信息
// 身份信息保存在服务器中, 此时也就不再有泄露的问题了
// 给浏览器返回的 Cookie 中只需要包含 sessionId 即可
String sessionId = UUID.randomUUID().toString();
sessions.put(sessionId, new User(userName, password));
respond.setHeaders(“Set-Cookie”, “sessionId=”+sessionId);
InputStream inputStream = HttpSeverV3.class.getClassLoader().getResourceAsStream(“LoginFinish.html”);
assert inputStream != null;
BufferedReader bufferedReader =new BufferedReader(new InputStreamReader(inputStream));
String line = null;
while ((line = bufferedReader.readLine()) != null) {
respond.setBody(line);
}
bufferedReader.close();
} else {
//登录失败
respond.setStatue(200);
respond.setMessage(“OK”);
respond.setHeaders(“Content-type”, “text/html”);
//登录失败应该让重写登录
InputStream inputStream = HttpSeverV3.class.getClassLoader().getResourceAsStream(“Test.html”);
assert inputStream != null;
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
//按行读取写入到body中
String line = null;
while ((line = bufferedReader.readLine()) != null) {
respond.setBody(line);
}
bufferedReader.close();
}
}
}
private void doGet(HttpRequest request, HttpRespond respond) throws IOException {
//返回一个html文件
if (request.getUrl().startsWith(“/ok”)) {
System.out.println(request);
//查看浏览器中是否有cookie 并且根据sessionId得到的用户的密码正确
String sessionId = request.getCookie(“sessionId”);
User user = sessions.get(sessionId);
if (user != null && “123”.equals(user.username) && “aaa”.equals(user.password)) {
//说明此时登录的用户就是主人直接返回简历
respond.setStatue(200);
respond.setMessage(“OK”);
respond.setHeaders(“Content-type”, “text/html”);
InputStream inputStream = HttpSeverV3.class.getClassLoader().getResourceAsStream(“LoginFinish.html”);
assert inputStream != null;
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
//按行读取写入到body中
String line = null;
while ((line = bufferedReader.readLine()) != null) {
respond.setBody(line);
}
bufferedReader.close();
} else {
respond.setHeaders(“Content-type”, “text/html”);
respond.setStatue(200);
respond.setMessage(“Ok”);
//在这里我们先获取类对象再获取类加载器 最后根据文件名在Resource目录中找到该文件 返回其InputStream对象
InputStream inputStream = HttpSeverV3.class.getClassLoader().getResourceAsStream(“Test.html”);
assert inputStream != null;
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
//按行读取写入到body中
String line = null;
while ((line = bufferedReader.readLine()) != null) {
respond.setBody(line);
}
bufferedReader.close();
}
}
}
public static void main(String[] args) throws IOException {
HttpSeverV3 v3 = new HttpSeverV3(9090);
v3.start();
}
}
登录界面代码
=====================================================================
<!doctype htpl>
 
用户登录
style=“width: 30%;margin:auto;background:rgb(195,195,195)”
bordercolor=“red” >
 请登录 用户名: 密码:



=====================================================================